Abstract
Purpose :
Prevention and early intervention of myopia can reduce the risk of sight threatening complications later in life. Our aims were: 1) to investigate differences in ocular parameters between children who become myopic (incident Myopes) to those who remained non-myopic over 1 year from multiple regions and 2) identify and quantify predictive risk factors for incident myopia.
Methods :
This is a retrospective analysis of 4 longitudinal population-based studies conducted in 3 locations including Northern Ireland, Sweden (non-Asian), and China (Asian) between 2013 and 2021. Children aged 6-16.9 years who were non-myopic at baseline were followed over 12 months. Cycloplegic refraction was measured with open field auto-refractors (Shin Nippon or Topcon). Axial length (AL) and corneal radius (CR) of curvature were taken using the IOL Master or Lenstar. Myopia was defined as spherical equivalent (SE) refractive error of ≤-0.50D. Data was analyzed by eyes after accounting for within subject correlation using a generalized estimating equation (GEE). The probability of incident myopia was modelled using a binary logistic regression. Factors included region (Asian/non-Asian), gender, age, SE, AL and ratio of AL by CR measured at baseline.
Results :
Data from 9182 children aged 8.1±1.6 years was available for analysis (n=8583 Asian and n=599 non-Asian). Incident myopes mean baseline SE was 0.11D (95% CI ±0.02), mean axial length 23.23mm (95% CI ±0.04) and AL/CR 2.98 (95%CI ±0.02). Mean SE, AL and AL/CR at baseline were significantly different between incident and non-incident myopes (p<0.001). Amongst incident myopes, Asian children were younger than non-Asian children (p<0.01) but there were no regional differences for SE, AL and AL/CR (p>0.21). Significant risk factors from the model were Asian region, female gender, younger ages, lower SE and higher AL/CR. There was a regional interaction with age and AL/CR. The model’s area under ROC curve was 93%. The relative risk of becoming myopic within 1 year in the Asian region compared to non-Asian region ranged from 2.3 to 6.0 based on risk factors. AL/CR was a better predictor than AL alone for risk of incident myopia.
Conclusions :
The regional risk of myopia onset within one year can be modelled based on age, gender, SE and AL/CR. The risk of incident myopia is higher in China compared to Sweden and Northern Ireland.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.